The outboard engine has undergone substantial changes in recent years. The outboard has for decades functioned as a two-cycle motor. Today, while the two cycle motors remain the standard, the use of fuel injection and computer control has become commonplace. Additionally, four-stroke outboard motors have been introduced in recent years, which also incorporate fuel injection.
The outboard engine has utilized carburetors of various forms for the mixture of fuel and air for introduction to a combustion chamber. With this method of presenting fuel for combustion, traditional technology emerged for measuring the amount of fuel consumed by the outboard engine. The technology incorporates measurement by means of a fuel meter. The device is located along a fuel line that connects the fuel supply tank and the outboard motor. This meter is used to determine the volume and rate of fuel consumed by the outboard engine.
The fuel meter commonly incorporates a mechanism such as an impeller. The fuel's motion, mass and volume move the impeller. Measurement of the impeller movement is correlated to an amount and rate of fuel consumed. Fuel meters have also incorporated an optical metering device to provide the fuel measurement. With such a device, fuel flows from the fuel supply tank to the outboard engine across an optical sensor, which obtains an optical measurement of the flow of fuel. This measurement is correlated to a fuel amount and rate of consumption.
Such fuel measurement devices are considered invasive because the measuring device being used is installed within the flow of fuel between the fuel supply tank and the engine. Such a device is disclosed in U.S. Pat. No. 4,590,796. As a result, the flow of fuel can be adversely affected by the measuring device. That is, with the introduction of one of these conventional fuel flow measuring devices, an uninterrupted flow of fuel from the supply tank to the engine cannot be obtained. This can have a negative impact on such characteristics as precision fuel measurement and fuel flow deprivation.
Other fuel measuring means, such as those of the type disclosed in U.S. Pat. No. 5,895,844, utilize multiple sensors that are modified to fit directly to and become part of the fuel injector. This means uses two physical sensors to invasively measure the physical position of the injectors' mechanical components.
Other fuel meters, such as those of the type disclosed in U.S. Pat. No. 4,596,216, measure fuel by measuring engine rotations per minute (RPM). In such systems, measurements of fuel rate and other fuel consumption parameters are dependent upon engine RPM.